Field of the Invention
The present invention relates to a vehicle control apparatus and a brake control apparatus, which are suitably used for a vehicle, such as a four-wheeled automobile.
Description of the Related Art
A brake control apparatus, for example, which is mounted in a vehicle, such as a four-wheeled automobile, includes a master-cylinder pressure control apparatus (that is, a first braking mechanism), a first control circuit, a wheel-cylinder pressure control apparatus (that is, a second braking mechanism), and a second control circuit. The master-cylinder pressure control apparatus controls a master-cylinder pressure generated in a master cylinder by an electric actuator based on an amount of braking operation performed by a driver. The first control circuit electrically controls the driving of the electric actuator of the first braking mechanism. The wheel-cylinder pressure control apparatus is provided between a wheel cylinder for braking provided on each wheel side of the vehicle and the master cylinder to variably control the master-cylinder pressure generated by the first braking mechanism as a wheel-cylinder pressure for each wheel so as to individually supply the wheel-cylinder pressure to the wheel cylinder of each wheel. The second control circuit electrically controls the driving of the second braking mechanism (for example, see Japanese Patent Application Laid-open No. 2011-73535).
A hydraulic-pressure sensor for detecting the master-cylinder pressure generated in the master cylinder is provided between the first control circuit and the second control circuit. The first control circuit controls the driving of the electric actuator of the first braking mechanism based on a detection value of the hydraulic-pressure sensor, to thereby control the master-cylinder pressure, whereas the second control circuit controls the wheel-cylinder pressure for each wheel side by the second braking mechanism based on the detection value of the hydraulic-pressure sensor.
By the way, in the related art described above, the following configuration is used to reduce the number of sensors, such as the hydraulic-pressure sensor. Specifically, the detection signal obtained by the single hydraulic-pressure sensor is used both to control the master-cylinder pressure by the first control circuit and to control the wheel-cylinder pressure by the second control circuit. Because of the above-mentioned configuration, for example, even if an abnormality in the sensor is detected as a result of the determination of whether or not the detection signal of the hydraulic-pressure sensor is abnormal, which is made by the first control circuit, the second control circuit continues the control by using the detection signal of the hydraulic-pressure sensor in some cases. As a result, there arises a problem in that it is difficult to ensure reliability of the control.